Plastic sheet compositions



Patented Apr. 7, 1936 UNITED STATES PATENT OFFICE No Drawing.Application July 7, 1934, Serial No. 734,238

6 Claims.

The present invention relates to a plastic composition, and itparticularly relates to plastic compositions which are highly suitablefor utilization in the manufacture of all building constructionmaterials, such as wallboards, shingles and so forth.

It has been found most plastic compositions utilized for manufacturingshingles and wallboards are not altogether satisfactory because ofexpense, lack of durability, low heat insulating power, or lowresistance to weather conditions normallyoccurring in the temperate zoneregions of the United States of America.

Although a great many plastic wallboards and shingle wallboardcompositions have been prepared from cellulosic materials with orwithout the addition of adhesive mixtures, many difficulties have beenencountered and completely satisfactory material has not as yet beenproduced.

It has now been found if the character of the cellulosic material and ifthe character of the adhesive materials are most carefully controlled,that most satisfactory plastic compositions will be formed for thepurpose above-described.

Among the most satisfactory materials which have been used are fibrouscellulosic materials, such as kapok, and sheet cellulose materials,preferably of a non-fibrous nature such as scrap Cellophane or othercellulose compound sheet material in divided condition. Cellophanerefers to transparent sheets or films of regenerated cellulose, made bydissolving pure wood pulp or similar cellulose to produce an aqueoussolution, the most common being viscose. The cellulose in this solutionis then precipitated by means of acids to produce a very thin,non-fibrous sheet of regenerated cellulose, which after being purifiedand impregnated with a softener, such as glycerin, is dried. Thefinished material has a glass-clear transparency, is smooth andlustrous, gasproof, greaseproof, and as the result of special treatmentis sometimes moisture-proof.

Kapok, strictly speaking, is the seed hair of Eriodendron anfractuosum,but the term is also applied to other vegetable downs. It is used as astuffing for lifesaving appliances at sea, due to its power of resistingthe penetration of water owing to the peculiar structure of the fiber.Kapok is a fibrous material in which the individual fibers are in theform of thin-walled tubes enclosing a relatively large volume of air.The cell wall represents on the average about one-fifth of the totaldiameter of the fiber.

These materials are preferably mixed with a proper adhesive such ascasein glue, the casein glue acting to form substantially integralcrystals or colloidal mass surrounding each of the kapok fibers and eachof the said cellulose scraps. Although the kapok and the scrap sheetcellulose material may be utilized together it has also been foundpossible to use them separately or in combination with the casein glue.

In lieu of mixtures of scrap cellulose material and kapok, it iscontemplated to use a mixture 10 of casein glue and kapok, or a mixtureof casein glue and scrap cellulose material.

In preparing the composition of the present application, one part ofkapok is thoroughly masticated with about an equal Weight of sheetcellulose scraps, preferably with the addition of water. When the kapokand the cellulose scraps have been thoroughly intermingled together, themoist mixture, from which most of the water is drained, is combined withhalf or an equal amount of casein glue and the resultant plasticcomposition is permitted to set either under pressure or in open vesselsto form sheet materials of desired thickness and width.

Preferably the kapok and the sheet scrap cellu- 5 lose material whenintermingled with the casein glue, should form a slurry or a cream whichit is found may be readily poured and set. The resultant compositionafter setting and hardening, may be readily machined, cut to size orplaned and it may be most desirably used for a material of construction.The preferred thickness is from one-eighth to one-quarter of an inch andin this thickness the material may be conveniently used forfireproofing, waterproofing, either in the form of wallboards or in theform of shingles.

The material is very cheap, has high insulating qualities anddurability, is very strong and of light weight.

By the expression Cellophane in the accompanying claims is includedscrap sheet regenerated cellulose materials, which may be sold underother and different trade-marks. The trade-mark Cellophane designatesthe product which has been. most widely sold and distributed upon themarket.

What is claimed is:

1. A plastic composition for building material consisting of kapokfiber, pieces of relatively thin sheets of regenerated cellulose, andcasein glue, said material being characterized by the fact that it isfireproof, waterproof and has a relatively low coefficient ofheat-conductivity.

2. The process of making a plastic composition for building materialwhich consists in masticating with water substantially equal parts byWeight of kapok fiber, and pieces of relatively thin sheets ofregenerated cellulose, draining the resulting moist mixture of thegreater part of the water and then adding casein glue, and permittingthe resultant plastic composition to set to form sheet material.

3. A plastic composition for building material consisting of kapok fiberand casein glue, said material being characterized by the fact that itis fireproof, Waterproof, and has a relatively low coeflicient of heatconductivity.

4. The process of making a plastic composition for building materialwhich consists in masticating kapok fiber with water to make a moistmixture, draining said mixture of the greater part of the water and thenadding casein glue, and permitting the resultant plastic composition toset to form sheet material.

5. A plastic composition for building material consisting of pieces ofrelatively thin sheets of regenerated cellulose and casein glue, saidmaterial being characterized by the fact that it is fireproof,waterproof, and has a relatively low coefficient of heat conductivity.

6. The process of making a plastic composition for building materialwhich consists in masticating with water pieces of relatively thinsheets of regenerated cellulose, draining the resulting moist mixture ofthe greater part of the water and then adding casein glue, andpermitting the resultant plastic composition to set to form sheetmaterial.

JOSEPH T. CASTLES, JR.

